1. Field of the Invention
This invention relates to a novel organic peroxide, use of the organic peroxide as a polymerization initiator, and a method for the polymerization of a monomer by the use of said organic peroxide as a polymerization initiator. More particularly, a high molecular polymer can be obtained with high efficiency by polymerizing a vinyl monomer in the presence of the organic peroxide as a radical polymerization initiator for the vinyl monomer. The polymer thus obtained has high strength and excels in flexibility and flowability. This invention further relates to a method for polymerization which is characterized by using the organic peroxide as a polymerization initiator.
2. Description of the Prior Art
The use of polymer materials in a wider range of fields in recent years has created a demand for polymers possessing various physical properties. It is known to the art that radical polymerization of a monomer effected by the use of a special initiator produces a modified polymer. As initiators of this sort, such polyfunctional polymerization initiators as 1,1-bis(t-butylperoxy)cyclohexane (Japanese Patent Public Disclosure SHO 54(1979)-107994, tris(t-butyl-peroxy)triazine (Japanese Patent Public Disclosure SHO 58(1983)-83008, and tri-t-butyl ester of pertrimellitic acid (Japanese Patent Public Disclosure SHO 61(1986)-231005 and such polymeric polymerization initiators as polyperoxy phthaloyl ["Journal of Industrial Chemistry", vol. 69, page 718 (1966)] have been disclosed. Further, Japanese Patent Public Disclosure HEI 3(1991)-174460 discloses modification of a resin by the use of a low-temperature decomposition type diacyl type organic peroxide possessing a repeating unit represented by the formula (1): ##STR2## (wherein 1 and n independently stand for an integer in the range of 1 to 20, m stands for 0 or an integer in the range of 1 to 5, and R.sub.1, R.sub.2,R.sub.3 and R.sub.4 independently stand for a hydrogen atom or an alkyl group of 1 to 5 carbon atoms, a cyclohexyl group, or a phenyl group).
To be specific, it is known that the use of such an initiator as 1,1-bis(t-butylperoxy)-cyclohexane enables a monomer to give rise to a polymer improved in resistance against heat and shock and that the use of an initiator such as tris(t-butyl-peroxy)triazine or tri-t-butyl ester of trimellitic acid enables production of a polymer having a backbone of the shape of a pentacle and exhibiting high strength and ideal flowability. It is further known that an attempt is being made to produce a block polymer possessing new physical properties by the use of such polymeric initiators as polyperoxy phthaloyl and that the use of a low-temperature decomposition type diacyl-based organic peroxide possessing a special structure enables production of a polymer with improved in brittle fracture behavior and strength which can resist repeated shocks.
In recent years, however, polymers have been put to a wider range of uses In many cases the quality required of the article shaped from the polymer has reached the point where the conventional method used for the production of the shaped article is no longer satisfactory. For the enhancement of the mechanical strength of a polymer, for example, it is known to use a method for giving the polymer an increased molecular weight by the use of such a special initiator as described above. Generally, however, the polymer produced suffers from degraded formability. In other words, a polymer which enjoys high mechanical strength and, at the same time, excels in formability cannot be obtained by merely increasing the molecular weight of the polymer. Even in the case of the method disclosed in Japanese Patent Public Disclosure HEI 3(1991)-174460, the effect cannot be called fully satisfactory in light of the severe requirements of the market. It is desired to develop a polymer which excels in formability and moreover enjoys higher mechanical strength than that of the conventional polymer and to perfect a polymerization initiator capable of enabling production of such an improved polymer.